軟球粒子各種電泳現象暨表面調節硬球粒子對平板之電泳運動之探討

Electrophoretic Behavior of Soft Particles and Electrophoretic Motion of a Charge-Regulated Sphere Normal to a Plane

唐于博(Yu-Po Tang)

指導教授 ： 李克強

國立臺灣大學/工學院/化學工程學研究所/博士(2004年)

https://doi.org/10.6342/NTU.2004.00213

摘要

本研究主要以假性光譜法對軟球粒子在各種系統下之電動力學現象進行數值模擬。其中包含軟球在球形孔洞中的電泳、考慮Charge Regulation現象的密集軟球懸浮系統的電泳現象、以及密集懸浮系統在交流電場下的振盪電泳現象。此外，我們也對具有Charge Regulation現象的硬球垂直於平板運動的現象做一個探討。

我們發現軟球電泳速度除了受到高分子層厚度、摩擦係數、固定電荷密度等物性的影響，同時也受到邊界效應、體積分率等的影響。同時，由於極化效應的影響，軟球粒子的電泳動度可能出現局部極大值與極小值。在考慮振盪電場下的電泳運動時，極化效應會使電泳速度產生極大值，並且振盪電泳速度的相角會有超前電場的現象。在硬球垂直於平板運動的現象中，我們發現當粒子越靠近平板時，此時粒子所感受到的拖曳力上升，因此電泳速度越慢。

另一方面有關於表面解離現象，當表面可解離的官能基數目增加時，粒子的電泳速度增加，而當溶液的pH值增加時，不利於解離反應的進行，因此電泳速度降低。

關鍵字

解離反應 ； 振盪電泳單位晶格模型 ； 孔洞 ； 軟球 ； 邊界效應

並列摘要

The electrophoretic behavior of the so-called “soft particle” is investigated in this study for various systems using pseudo-spectral method. The analyses include the electrophoretic motion of soft particle in spherical cavity, the electrophoretic motion of concentrated suspension of soft particles with charge-regulated polymeric layer, and the dynamic electrophoretic mobility of concentrated suspension of soft particles. In addition, the electrophoretic motion of a spherical particle with charge regulated surface normal to a plane is studied also.

We found that the electrophoretic mobility of soft particles is affected by several factors: the thickness of the polymeric layer, the friction factor and the fix charge density within the polymeric layer, the presence of boundary, and the volume fraction of the particles. Due to the polarization effect, the magnitude of the scaled dynamic mobility has a local maximum as the dimensionless oscillation frequency increases, and the corresponding phase angle has a lead over that of the electric field.

In the electrophoretic motion of a spherical colloid moving normal to a plane, we found that the closer the particle to the plane, the slower the mobility. This is because the presence of the boundary enhances the hydrodynamic drag on the colloid.

As for the charge regulation phenomena, we found that the higher the number of functional groups, the greater the mobility of the particle; yet the higher the pH of the solution, the lower the mobility. This is because the high ion concentration suppresses the dissociation reaction.

並列關鍵字

boundary effect ； unit cell model ； charge regulation ； cavity ； dynamic mobility ； soft particle

參考文獻

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